How do you keep busy when you’re snowed in during a blizzard? With a huge snowball fight of course.

On Saturday, over 5,000 participants had registered for the Dupont Circle Snowball Fight group on Facebook, with the epic battle to take place at 2 p.m. D.C. Mayor Adrian Fenty dropped in to shake hands and police were in abundance to make sure things stayed relatively calm.

Ami Greener and Michael Lipin attempted to organize a massive snowball fight via Facebook during the big snowstorm in December, but only about 6 people showed. With this attempt, however, they learned how to leverage Twitter to spread the word much more quickly.

“I tweeted it with hash tags like Snowmaggedon, Snowpocalypse, that kind of thing,” Greener says.

Lipin adds, “It went viral. I’ve never seen anything like this. We had 33 members on Thursday morning, and it’s growing by hundreds an hour right now.”

Of course, any good snowball fight needs to have a disclaimer.

“You are coming to Dupont Circle Park on Saturday, Feb 6, 2010, to play snowballs voluntarily. The people spreading the word about the happening are not preparing any special equipment or conditions and may not be held responsible for your decisions and/or actions.”

Greener and Lipin will go their separate ways once the snow starts flying, with Lipin siding with Dupont South and Greener with the Dupont North.